Check your USB connections for a snug fit or frayed cables, missing pins.If using a hub, try using a different port on your Mac for the hub or plugging your external drives directly into the Mac.Quick Tips Follow these quick tips and get your Mac to recognize and mount your external drives

When you wake your Mac up, for whatever reason, your external drive does not wake up. If you have a disk already mounted and your system goes to sleep, it also powers down ports, including USB ports. There are several reasons why your Mac won’t recognize a drive. In many cases, the only way to solve this problem is to completely remove the external drives and then restart your MacBook or Mac several times until the drives finally show up again. It won’t mount at all and acts as if it’s utterly invisible to macOS.

This situation often occurs after you initially eject the external drive and unplug it from your computer. When you try to plug in the drive again, your Mac no longer sees it. Sometimes our MacBooks, MacBook Pros, or Macs don’t recognize our external drives or external thumb drives.

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